Nobuto Kageyama

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We report on our recent development of high power 940 nm laser diodes (LDs) bars. The optimization of the laser structure and thermal management allow over 200-W continuous wave (CW) operation with 58% conversion efficiency from the 1-cm LD bar. We have also developed an assembly technique, and have suppressed the smile of LD bars mounted even on Cu(More)
We have demonstrated a high-power 980-nm vertical-cavity surface-emitting laser diode (VCSEL) array with ion-implanted current apertures. The device was characterized on an exclusively developed water-cooled heat sink for the VCSEL array. A peak output power of over 200 W has been achieved under quasi-continuous-wave operation at a cooling water temperature(More)
We report on our recent development of quasi-continuous-wave 940-nm laser diode (LD) bars with passive cooled type. The 10 LD bar stacks with a narrow pitch of 1.54 mm have demonstrated a high output power of 10.1 kW, corresponding to 1 kW/bar, under 200-μs pulses at 50-Hz operating frequency. The maximum conversion efficiency of 58% has been(More)
We report a high-average-power laser-diode-pumped Nd:YAG master oscillator power amplifier system that has a minimum number of elements in the single multipass zigzag-slab amplifier stage and is used to pump a high-peak-power and high-average-power Ti:sapphire laser system. This phase-conjugated system produces an average power of 362 W at 1 kHz in a 30-ns(More)
For large-area ion-implanted vertical-cavity surface-emitting lasers (VCSELs), side emission from the edges of a chip disturbs the laser emission of a VCSEL mode, and suppression of it is fundamental. In this paper, we present results of a numerical investigation of the side emission from large-area VCSELs. We have modeled a VCSEL structure by an infinitely(More)
We have developed the 915 nm single emitter LDs with a window structure. A high output power of 20.2 W and a power conversion efficiency of 66% at 10°C have been obtained without COMD. We have also developed the 940 nm LD bars using the thermal expansion controlled assembly technology. As a result, the smile has been successfully suppressed down to(More)
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